Well: why call something an orc-wight when it refers to something hypothetical which doesn't have anything to do with the actual orcs in the stories? Neither in The Hobbit, LoTR or the published Silmarillion we find anything about orc-wights or orcs that would fit this description. I'm not very interested in speculations about "what might have been", but the stories that actually have been published.

I'm aware that Tolkien re-wrote and mused about changing or tweaking some of the concepts or ideas he introduced in his published stories. He also seems to have struggled with several of the criticisms he got against the orcs, ("creatures that are considered irredeemable etc.) It's a long time since I've read anything of Unfinished Tales and the HoME material, but much of what I've read in these works are simply might-have-beens, early concepts, abandoned ideas or Tolkien trying to develop or elaborate on (unexplored) parts of the stories, but failing to either finish them or produce stories which are reasonably self-consistent. This is also why I generally don't think they're a good basis for discussing Tolkien's written works nor an acceptable source for adaptation of films. Much of these books seem more like a basis for exploring how Tolkien worked creatively, ideas he abandonded, how he developed his mythology (as well as LoTR) from its early basis, and projects he had for more individual works within the big tapestry of his mythology.

With regard to the individual works, I acknowledge a notable difference these more developed "individual stories" and the drafts Tolkien writes about different topics. The two lays of Beleriands and stories like "Of Tuor's coming to Vinyamar" and "Narn i Hin Húrin", "The mariner's wife" and the story taking place among the Druedain are much more consistent and developed than the series of brief drafts we get in the essays on The Istari and the palantirs and even "The Hunt for the Ring". Artistically they are works in their own right that I can relate to and consider suitable as a basis for discussion, since they are much more fully developed and have a greater sense of internal logic. When it comes to those parts of UT which are not self-consistent stories, I find that Tolkien's letters are as a rule much more detailed and satisfactory.

I haven't read a single page of Morgoth's Ring, so for all I know this might be a very different work from the others in the HoME series.